The government enacted a law on Nov. 22 to address the risks posed by tsunami in the event of a major earthquake occurring in the Pacific Ocean off the coasts of central and western parts of the country.
The special measures law outlines actions to be taken should a major quake occur along the Nankai Trough, an undersea trench in the Pacific that stretches from the Izu Peninsula, southwest of Tokyo, past Shikoku to Kyushu.
The area is thought to have experienced major quakes about once every 100 to 150 years, with a quake of magnitude 9 — the same as the Great East Japan Earthquake of 2011 — believed to strike about once every 1,000 years.